Apparatus for folding and stacking flexible sheets

ABSTRACT

AN APPARATUS FOR SEQUENTIALLY FOLDING AND STACKING INDIVIDUALLY RECEIVED SHEETS OF A FLEXIBLE MATERIAL TO PREPARE COUNTED STACKS OF THE FOLDED SHEETS FOR SUBSEQUENT PACKAGING. THE ILLUSTRATED EMBODIMENT OF THE APPARATUS INCLUDES MEANS FOR CONVEYING THE INDIVIDUAL SHEETS ALONG A PATH OF TRAVEL, FIRST TRANSVERSE FOLDING MEANS POSITIONED INTERMEDIATE THE PATH OF TRAVEL FOR FOLDING EACH SHEET UPON ITSELF ALONG A TRANSVERSE FOLD LINE, SECOND TRANSVERSE FOLDING MEANS POSITIONED INTERMEDIATE THE PATH OF TRAVEL AND SUBSEQUENT TO THE FIRST FOLDING MEANS FOR IMPARTING A SECOND TRANSVERSE FOLD, AND LONGITUDINAL FOLDING MEANS ADJACENT THE TERMINAL END OF THE PATH OF TRAVEL FOR IMPARTING A LONGITUDIANL FOLD. THE THUS FOLDED SHEETS ARE THEN DELIVERED TO A PLATFORM WHICH SEQUENCES DOWNWARDLY UPON RECEIVING EACH FOLDED SHEET SUCH THAT THE LEVEL AT WHICH THE FOLDED SHEETS ARE RECEIVED ON THE PLATFORM REMAINS SUBSTANTIALLY CONSTANT. WHEN THE PLATFORM REACHES ITS LOWEST POSITION A DELIVERY BELT IS ACUATED TO REMOVE THE STACK OF FOLDED SHEETS FROM THE PLATFORM AND TRANSPORT THE SAME TO A PACKAGING STATION.

Nov. 14,1972 R. K. TEED 3,702,696

APPARATUS FOR FOLDING AND STAGKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9Sheets-Sheet 1 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING ANDSTACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 2 Nov. 14,1972 v R. K. TEED 3,702,695

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9Sheets-Sheet 5 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING ANDSTACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 4 R. K. TEEDNov. 14,1972

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9Sheets-Sheet 5 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING ANDSTACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 6 Nov. 14,1972 I T D 3,702,695

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9Sheets-Sheet 7 III i 0 Z" 'J) HZ @Z) 58 LOG-1C RELAY Moouue Loam:\"\ooul e R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKINGFLEXIBLE SHEETS FiledFeb. 18, 1971 9 Sheets-Sheet 8 momsow ma :mmmma R.K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETSFiled Feb. 18, 1971 9 Sheets-Sheet 9 wdammwua United States PatentOflice 3,702,696 Patented Nov. 14, 1972 US. Cl. 270-66 9 Claims ABSTRACTOF THE DISCLOSURE An apparatus for sequentially folding and stackingindividually received sheets of a flexible material to prepare countedstacks of the folded sheets for subsequent packaging. The illustratedembodiment of the apparatus includes means for conveying the individualsheets along a path of travel, first transverse folding means positionedintermediate the path of travel for folding each sheet upon itself alonga transverse fold line, second transverse folding means positionedintermediate the path of travel and subsequent to the first foldingmeans for imparting a second transverse fold, and longitudinal foldingmeans adjacent the terminal end of the path of travel for imparting alongitudinal fold. The thus folded sheets are then delivered to aplatform which sequences downwardly upon receiving each folded sheetsuch that the level at which the folded sheets are received on theplatform remains substantially constant. When the platform reaches itslowest position a delivery belt is actuated to remove the stack offolded sheets from the platform and transport the same to a packagingstation.

The present invention relates to an apparatus for automaticallyprocessing individual pieces of relatively limp sheet material such aslightweight blankets, towels, diapers and the like. More particularly,the apparatus is adapted to sequentially fold a plurality of flexiblesheets along two perpendicular fold lines, and to pile the folded sheetsin stacks containing a predetermined number.

In the manufacture of many textile products, it is conventional to cutindividual articles from a continuous length of textile material, and toseparately process each article, such as by stitching along the fouredges. At the conclusion of the required manufacturing operations, themachine sequentially delivers the finished articles to a delivery tableor the like, where the products are picked up and folded by hand andplaced in separate stacks of a predetermined number suitable for finalpackaging. A machine of this general type is described in copendingapplication, 'Ser. No. 853,255, filed Aug. 26, 1969, now US. Pat. No.3,580,198, issued May 25, 1971, and which is assigned to the assignee ofthe present invention.

It will be readily appreciated that the efiiciency of automaticprocessing machines of the above type is severely limited by therequired manual folding and stacking operations. In particular, thesemanual operations are too slow for high volume production, and areincapable of providing identically folded articles in a neat stack. Inaddition, the use of manual labor signiflcantly increases the cost ofthe process.

Accordingly, it is an object of the present invention to provide anapparatus for efficiently and automatically folding and stackingflexible sheets of the described type, and wherein the above noteddisadvantages of the manual operations are eliminated.

It is a more particular object of the present invention to provide anapparatus which is adapted to automatically fold flexible sheets alongat least one transverse fold line, as well as along a longitudinal foldline, and to prepare and deliver counted stacks of the folded sheets forpackaging.

These and other objects and advantages of the present invention areachieved in the embodiment illustrated herein by the provision of anapparatus which includes conveyor means for conveying the individualsheets along a path of travel, and transverse folding means positionedintermediate the path of travel for sequentially folding each sheetalong a transverse fold line. A longitudinally disposed rod ispositioned adjacent the terminal end of the conveyor means and isprogrammed to lift each transversely folded sheet and fold the samealong the longitudinal fold line formed by the rod. The rod thentransports the folded sheets to a platform which is adapted tosequentially receive the sheets to form a vertical stack. The platformis designed to be lowered an increment approximately equal to thethickness of a folded sheet upon receipt of each sheet from thelongitudinal rod, and to cooperate with a conveyor upon receiving apredetermined number of sheets for removal of the stack from theplatform.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds, when taken in connectionwith the accompanying drawings, in which FIG. 1 is a schematicillustration of the folding and stacking apparatus of the presentinvention;

FIG. 2 is a schematic illustration of the folding portion of theapparatus shown in FIG. 1, and particularly illustrating the drivearrangement for the various conveyor rollers;

FIG. 3 is a fragmentary side view, partly sectioned, of the one-wayclutch for actuating the final delivery belts, and taken substantiallyalong the line 3-3 of FIG. 1;

FIG. 4 is a top plan view of the transfer mechanism and stackingapparatus of the present invention;

FIG. 5 is a side view, partly sectioned, illustrating the details of thetransfer mechanism;

FIG. 6 is a sectional view taken substantially along the line 6-6 ofFIG. 4 and illustrating the platform at its elevated position;

FIG. 7 is a sectional view corresponding to the lefthand portion of FIG.6 with the delivery belts being omitted for purposes of clarity;

FIG. 8 is an end view facing opposite the view in FIG. 7 andillustrating the platform at its lowered position;

FIG. 9 is a schematic illustration of the first and second transversefolding stations of the present invention;

FIG. 10 is a schematic diagram of the electrical control system for thetransverse folding stations illustrated in FIG. 9;

FIG. 11 is a schematic wiring diagram for the longitudinal folding andtransfer mechanism; and

FIG. 12 is a schematic wiring diagram for the platform indexing and thedelivery belt actuating mechanisms.

Referring more specifically to the drawings, the overall features of theinvention will first be described with reference to FIG. 1. Inparticular, the apparatus includes conveyor means 20 including anendless conveyor belt 21 for conveying individual sheets 22 of aflexible textile material or the like along a first path of traveldefined by the belt 21 from an adjacent fabricating or treatingapparatus (not shown) such as the one described in the above-identifiedcopending application. First transverse folding means 24 is positionedalong the first path of travel ahd beneath the discharge end of the belt21, and is adapted to sequentially fold each sheet upon itself along afirst transverse fold line.

Conveyor means 20 further includes a second endless conveyor belt 28 forconveying the transversely folded sheet from the folding means 24 alonga second path of travel defined by the belt 28. Second transversefolding means 30 is disposed below the discharge end of the belt 28 andis adapted to again fold each sheet upon itself to impart a secondtransverse fold therein. A third endless conveyor belt 34 is providedfor conveying the twice folding sheet from the second folding means 30along a third path of travel defined by the belt 34 to a terminal end35.

Means 40 is provided for longitudinally folding the individual sheets asthey arrive at the end 35, and includes a longitudinally disposed rod 42which is initially positioned below the terminal end 35. The rod 42 issequentially actuated to lift each transversely folded sheet from theconveyor belt 34, to fold the same upon itself along a longitudinal foldline formed by the rod, and to transport the folded sheet transverselyfrom the third path of travel and deposit the same onto the platformmeans 44 to form a stack thereon. Platform means 44 includes theplatform 46, and means including the piston 48 and pneumatic cylinder 49(FIG. 12) for vertically translating the platform 46 between an elevatedand a lowered position. Delivery belts 50 are provided for removing astack of a predetermined number of folded sheets from the platform 46and delivering the same in condition for packagmg.

All of the above generally described features and the more specificallydescribed features below are suitably mounted on a common interconnectedframe 164. The frame 164 has been shown in part only in the drawing forsimplicity of illustration and it is to be understood that this framecarries all of the elements of the apparatus of this invention.

To now describe the various features of the present invention morespecifically, FIGS. 1 and 9 illustrate the conveyor means 20 whichincludes the horizontal endless belt 21 which is driven at a constantspeed by a conventional motor (not shown). As shown in FIG. 1, the belt21 is longitudinally split into two spaced segments such that a verticalbeam of light may be passed therethrough for the purposes hereinafterstated. The belt 21 is disposed about the end roller 54 to define adischarge end such that the leading portion of the sheet 22 which isbeing fed along the upper surface of the belt will drape verticallydownwardly into a position to be engaged by the first folding means 24as seen in FIG. 1.

The first folding means 24 includes a conventional photoelectricproximity sensor 56 for detecting the presence or absence of a sheet onthe belt 21. A transverse bar 58 is disposed below the discharge end ofthe belt 21 and is longitudinally translatable by a cam 60 and follower62 such that the bar 58 is advanced longitudinally beyond the end of thebelt 21 to engage a sheet at its approximate mid-portion when the sensor56 detects the trailing edge of a sheet 22. A pair of cooperating niprollers 64 and 65 are aligned with the bar such that the advance of thebar will direct a sheet into the nip of the rollers. The rollers arerotated at a constant speed in opposite directions by an arrangementhereinafter described, such that the sheet will be drawn through therollers and thus folded upon itself.

An upper endless conveyor belt 68 is disposed about the rollers 64 and70, and immediately above the endless conveyor belt 28 which in turn isdisposed about the rollers 65 and 72. Viewing FIG. 2, it will beobserved that the belts 28 and 68 are driven at corresponding speeds inopposite directions by a drive train which includes an electric motor74, reduction gear box 75, main drive shaft 76, drive chain 77, idlershaft 78, drive chain 79, shaft 80 mounting roller 65, shaft 81 carryinggear 82, and shaft 83 carrying cooperating gear 84 and roller 70. Thefar end of shaft 83 mounts a drive chain 85 for rotating shaft 86mounting roller 64. As will be apparent, the transversely folded sheet22 passing through the nip rollers 64 and 65 will be conveyed betweenthe belts 28 and 68,

and the leading end thereof will subsequently pass over the roller 72and drape vertically downwardly into a position to be engaged by thesecond folding means 30. As seen in FIG. 1, the belts 28 and 68 are alsolongitudinally slit into two spaced segments to permit observation ofthe sheets 22 from above.

The second folding means 30 includes a photoelectric proximity sensor 90positioned to detect the presence or absence of a sheet being conveyedbetween the belts 28 and 68, and a transverse bar 92 disposed below theroller 72. The bar 92 is longitudinally translatable by the cam 94 andfollower 95 in a manner similar to the advance of bar 58, and a pair ofcooperating niprollers 96 and 97 are aligned with the bar to receive andfold the sheet in a manner equivalent to that described above withrespect to folding means 24.

The control arrangement for selectively longitudinally translating thetransverse bar 58 of the first transverse folding means 24 includes ashaft 100 (FIG. 2) carrying an identically configured cam 60' on the farside of the belt 21. The shaft 100 is connected to the main drive shaft76 through a brake 102 and clutch 104, and a drive chain 106. Thus whenthe brake 102 is disengaged and the clutch 104 engaged, shaft 100 willbe rotated by the shaft 76, but when the brake is engaged and the clutchdisengaged, the shaft 100 will remain stationary. The followers 62 and62' associated with the cams 60 and 60' each comprise a longitudinallydisposed rod mounting the bar 58 at the forward end thereof, andsuitable guide blocks 109 serve to guide the follower rods in thelongitudinal direction. Viewing FIG. 9 it will be observed that the cams60 and 60' include an internal cam surface 111 for guiding the followers62 and 62', and an external cam surface 112 controlling actuation of aswitch 114.

The second folding means 30 includes a similar control arrangement whichincludes earns 94 and 94 carried by shaft 116 on opposite sides of thebelt 28, with the shaft 116 being connected to the main drive shaft 76through a brake 118, clutch 119, and drive chain 120. The followers 95and 95' include longitudinal rods which in turn mount the bar 92, andthe cams 94 and 94' include an internal cam surface 124 for guiding thefollowers 95 and 95', and an external cam surface 125 for controllingactuation of a switch 126.

A suitable electrical circuit for selectively actuating the first andsecond folding means 24 and 30 is illustrated schematically in FIG. 10.The circuit is of a conventional design we'll known to those skilled inthe art, and includes a photoelectric relay 128, such as Model TR4-3manufactured by Farmer Electric Products Company, Inc. of Natic k,Mass., which is associated with the sensor 56 and is adapted to latch inits relay upon a signal from the sensor indicating that the trailingedge of the sheet 22 is passing beneath it on the belt 21. The brake10-2 is thereby released and clutch 104 engaged to cause the shaft 100to rotate clockwise as seen in FIG. 10. The shaft rotates until theraised portion of the cam 60 trips switch 114 to drop out the relay 128.The cam then coasts until switch 114 drops off the raised portion toengage the brake 102, wherein the system is ready-for the next cycle.

A similar photoelectric relay is associated with the sensor 90 of thesecond folding means 30. -In this case however, a timer 131, such asmodel 120T manufactured by Farmer Electric, is positioned to trip therelay 130 a preselected time interval after the sensor 90 detects thetrailing edge of the folded sheet. The relay acts to rotate the shaft116 of cam 94 and trip the switch 126 in a manner similar to thatdescribed above with reference to the first folding means 24. Inaddition, a pair of manual override switches 132 and 133 are providedfor each of the folding means to permit manual resetting of theassociated relay circuits.

After the sheets 22 are twice folded in the manner described above, theyare conveyed along the upper surface of belt 34 to the terminal end at35. The belt 34 is disposed about the lower nip roller 97 and a terminalroller 136, and it will be seen that the belt is longitudinally splitinto two spaced segments for the purposes to become apparent. The belt34 cooperates with an overlying belt 138 disposed between the upper niprollers 96 and roller 139, and the two belts are connected to the maindrive shaft 76 by an arrangement including the clutch 140, and drivechains 142 and 143 connecting shaft 144. The shaft 144 extends throughthe belt 34, and carries drive chains 145 and 146 on the far side asseen in FIG. 2 for rotating shafts 147 and 148 respectively carryingrollers 97 and 136, and it will be seen that the belt is longitudinallysplit which mates with the gear 150 of shaft 152 to turn the roller 139.The far end of shaft 152 carries a drive chain 154 interconnecting theshaft 156 which mounts nip roller 96. A brake 158 is mounted on shaft148 such that when the brake is engaged and the clutch 140 disengaged,the belts 34 and 138 may be held stationary, and when the brake isdisengaged and the clutch engaged, the two belts are rotated atcorresponding speeds. A switch 160 is positioned below the terminal end35 of the conveyor means 20 as seen in FIG. 1, with the switch includingan upwardly directed actuating arm 161 extending through the openingbetween the belt segments so as to be contacted by a folded sheet beingconveyed along the belt 34.

The longitudinal folding means 40 includes a frame 164- positionedadjacent the terminal end 35, with the frame mounting a carrier 165which is longitudinally translatable along the rods 166 and 167. Thecarrier is translated by movement of the piston 168 in the pneumaticcylinder 169 which is secured to the frame, with the piston beingconnected to the carrier by the cord and pulley arrangement 170 as seenin FIG. 1. Thus, when the piston 168 is translated in one direction, thecarrier 165 is translated in the opposite direction.

The carrier 165 includes a longitudinal shaft 172 rotatably mounting agear 174 and interconnected lever arm 175. A side arm 176 on the carriermounts a pneumatic cylinder 178 having a piston 179 (FIG. 11), and agear rack 180 is connected to the piston and translatable therewith. Therack 180 operatively engages the gear 174, and thus movement of thepiston 179 in the cylinder 178 will cause the rack to be translated andthe gear 174 and lever arm 175 to rotate through the are indicated indashed lines in FIG. 1. The remote end of the lever arm 175 mounts therod 42 which is initially positioned to extend longitudinally into theopening between the segments of the belt 34, but somewhat beneath theupper surface thereof. It should also be noted that two switches 182 and183 are carried by the frame 164 adjacent the periphery of the gear 174,with the gear 174 including an actuating arm 184 positioned to actuatethe switch 182 approximately midway through the arcuate translation ofthe rod 42. The switch 183 is actuated by the arm 184 when the rod 42reaches its terminal position adjacent the platform means 44. Inaddition, three switches numbered 185, 186, and 187 are carried by theframe in position to be contacted by the carrier 165 as it is translatedrearwardly along the rods 166 and 167. The function of these switcheswill be further explained below.

As seen in FIGS. 4 and 5, the rod 42 is hollow and includes a pluralityof radially directed openings 189. A vacuum line 190 extends along thelength of the lever arm 175 and communicates with the hollow rod suchthat the vacuum, in the line 190 evacuates the hollow core of the rodand causes air to be drawn inwardly through the radial openings for thepurposes hereinafter described. A conven tional vacuum transducer 192which converts air pressure to vacuum is used to control the flow of airthrough the line 190.

A suitable electrical control arrangement for actuating theabove-described longitudinal folding means 40 is illustratedschematically in FIG. 11. As will be apparent from a study of thisillustration, the arrival of a folded sheet 2 2 at the terminal end 35actuates the switch 160 which in turn closes the solenoids 195 and 196.Solenoid 195 closes the solenoid 198 and also controls the timer 200which is designed to shut down the apparatus if a jam up or stoppageoccurs. More particularly, if the switch stays closed longer than apreselected interval set on the timer 200, the power is cut to theholding coil 205 which stops the motor 74 and thus the entire apparatus.Corrective ac tion is then necessary to restart the machine. Solenoid198 actuates the counter 201 and turns on the air valve 203 connectingpressure source 202 to the transducer 192, and also actuates thesolenoid 204. The closing of solenoid 196 opens the line to the solenoid206 of the carriage pneumatic valve 207, and engages the brake 158 anddisengages the clutch 140 to thereby terminate movement of the belts 34and 138.

The closing of solenoid 204 actuates the solenoid 208 of the pneumaticvalve 210 which directs the pneumatic pressure into the cylinder 178 totranslate the piston 179 toward the left as seen in FIG. 11. This inturn draws the rack 180 across the gear 174 to arcuately translate thelever arm 175 and rod 42. During movement of the lever arm and rod, theswitch 182 is opened to release the holding circuit to solenoid 195.When the arm reaches its terminal point, the switch 183 moves fromcontact 211 to contact 212 to release the holding circuit to solenoid198 and thereby turn off the air passing through the valve 203. Closingcontact 212 actuates the solenoid 213 which in turn actuates solenoid214 controlling the pneumatic valve 207 connected to cylinder 169. Thisin turn causes the carrier to be translated rearwardly or toward theright as seen schematically in FIG. 11, and upon reaching its mostrearward position, the switch 185 is closed and switches 186 and 187 areopened. Switch 186 releases solenoid 204 to thereby close solenoid 215and rotate the lever arm through a reverse arc. The opening of switch187 releases the solenoid 2113 to return the carrier to its originalposition by actuating solenoid 206. The closing of normally open switchcontrols the movement of the platform means 44 as hereinafter described.To complete the description of the circuit shown in FIG. 11, it will benoted that there is a manual restart switch 216 and an off-on switch217.

The structural details of the platform means 44 for receiving the foldedsheets are best illustrated in FIGS. 6-8 and 12. Generally, the platformmeans includes the platform 46 which is adapted to receive and supportthe folded sheets 22. The platform is in turn supported by thevertically translatable support rod 218 which is connected to the piston48 in the cylinder 49. The cylinder 49 is operatively connected throughthe valve 220 to the pressure source 202 such that upon opening thevalve 220 the platform is lifted to its elevated position.

Means are further provided for sequentially lowering the platform fromits elevated position to its lowered position such that the platform islowered an increment approximately equal to the thickness of a foldedsheet upon receipt of each sheet to thereby form a vertical stack ofsheets on the platform having a consistent elevation approximately equalto that of the platform at its elevated position. To accomplish thispurpose, a pair of oppositely directed racks 221 and 222 are secured tothe support rod 218, with each of the racks mounting nine verticallyspaced teeth 223 and 224 respectively. It will be noted that the teethon the two racks are vertically olfset from each other such that theteeth on one rack are positioned at a level intermediate the teeth onthe opposite rack.

A double pole switch 226 is mounted adjacent the rack 222 and includesan actuating arm 227 which is adapted to ride along the teeth 224. Asecond double pole switch 230 is positioned adjacent the rack 221, andincludes a similar actuating arm 231. As will be apparent from FIGS.6-8, the switches 226 and 230 will close one pole when the arm islaterally lifted by one of the teeth, and will close the opposite polewhen the lever arm is positioned intermediate two teeth. By design,these two switches will be actuated in an alternate fashion.

A pair of pneumatically actuated slide arms 234 and 235 are also mountedadjacent the two racks with the slide arm 234 adapted to be translatedinto operative engagement with one of the teeth 224, and the slide arm235 adapted to operatively engage one of the teeth 223. The two slidearms 234 and 235 are controlled by the valves 238 and 239 respectively,and it will be observed in FIG. 12 that both of the arms arespring-biased in a direction away from the racks such that they willengage the associated teeth only when the valve is connected to thepressure source 202.

The illustrated apparatus further includes means for removing the stackof folded sheets from the platform 46 upon the platform reaching itslowered position. In this regard, it will be noted that the platformincludes a number of spaced parallel slots 242 extending in alongitudinal direction through the platform, note FIG. 4. A plurality ofspaced parallel conveyor belts 50 are positioned below the platform atan elevation slightly above that of the platform at its lowered positionwith each of the belts 50 adapted to communicate with one of theplatform slots 242. Thus as the platform reaches its lowered position,the stack of sheets 22 positioned thereon will be substantiallysupported by the belts 50.

The belts 50 are selectively actuated upon the platform reaching itslowered position to withdraw the stack of sheets therefrom in the mannerbest illustrated in FIG. 1. For this purpose, a pneumatic cylinder 244is mounted adjacent the delivery belts 50 and includes a following rack246 which engages the one-way clutch 248, shown in detail in FIG. 3. Therack further carries an actuating arm 259 adapted to contact switch 260when in its withdrawn position, and to contact switch 261 when in itsextended position.

The clutch 248 is carried by the shaft 250 for actuating the sprocketand drive chain 252. The drive chain 252 is in turn connected to theshafts 253 and 254 which carry a forward roller 256 and a rear roller257 respectively. As best seen in FIG. 1, actuation of the pneumaticcylinder 244 causes the rack 246 to translate toward the right, which inturn acts through the clutch 248 to rotate the rollers 256 and 257 andthus the delivery belts 50. When the rack 246 wthdraws to its originalposition, the clutch 248 serves to prevent reverse rotation of thesemembers.

The operation of the platform means 44 will be more fully understood byreference to the exemplary circuit illustrated in FIG. 12. The circuitincludes switch 185 which, as explained above, is closed when thecarrier 165 is withdrawn to its rearward position. The closing of switch185 directs current through switches 226 and 230 to the solenoids 265and 266 which respectively advances the slide arm 234 into engagementwith the teeth 224 and withdraws the slide arm 235 from the teeth 223.Thus the rod 218 is dropped a distance equal to one-half the spacingbetween the adjacent teeth on the racks. Upon the next closing of theswitch 185, the switches 226 and 230 will be positioned on the oppositepoles as shown in FIG. 12 by reason of the fact that the rod 218 hasdropped an increment equal to one-half the distance between adjacentteeth. Thus the solenoids 268 and 269 will be actuated, and the sidearms will return to their original positions. This causes the rod 218 todrop a second increment.

The above operation continues until the racks reach the position shownin FIG. 8 wherein the platform 46 is ready to receive the last foldedsheet. In this configuration, the followers 227 and 231 are both abovethe last tooth of the associated rack, and thus when the last sheet isreceived the subsequent electrical impulse will retract both slides 234and 235 and the racks will drop to permit the arm 273 to close switch272. Closing switch 272 directs current through the normally closedswitch 260 to solenoid 275, which in turn closes solenoid 277controlling the valve 278 to cylinder 244. The switch 260 is opened uponmovement of the arm 259 on rack 246, but the solenoid 275 remains closedby reason of the holding circuit through switch 261. When the rack 246reaches its outer limit, pole 280 of switch 261 is opened to release theholding circuit to solenoid 275 and thus permit the return of the rack.Simultaneously, the pole 281 of switch 261 is closed to actuate thesolenoid 282. This in turn closes the solenoid 284 which opens the valve20 to lift the platform upwardly to its elevated position. When theelevated position is reached, the lower pole 287 of switch 288 opens torelease the solenoid 282, and the upper pole 289 is closed to energizethe solenoid 269 to slide in the arm 235 under the lowest tooth on rack221. A manual override switch is provided at 290 to re-set the stackerwhen desired.

It is believed that the overall operation of the apparatus will beapparent from the above detailed description. To briefly summarize itsoperation however, the flexible sheets to be folded and stacked areindividually positioned on the belt 21 and conveyed along the uppersurface thereof until the leading edge of the sheet is draped over theend defined by the roller 54. By design, the sensor 56 is positioned tosense the trailing edge of the sheet when the mid-portion thereof isopposite the transverse bar 58. Thus, translation of the bar 58 causesthe mid-portion 0f the sheet to be inserted between the oppositelyrotating nip rollers 64 and 65. The folded sheet is then conveyed alongthe belt 28 and the folding process is repeated by the second foldingmeans 30. In this case however, the sensor is positioned to sense thetrailing edge prior to the mid-portion reaching the bar 92, with thetimer 131 (FIG. 10) being programmed to delay actuation of the bar untilthe mid-portion is reached.

As the twice folded sheets approach the terminal end 35 of conveyormeans 20, the switch is closed. This actuates the circuit shown in FIG.11, and results in the rod 42, which is initially positioned .below theterminal end, to be translated through a first are extending to a secondposition immediately overlying the platform 46. Concurrently, air valve203 will be opened to actuate the transducer 192 and create a vacuum inrod 42 to thereby facilitate the accurate folding of the sheet on therod. The vacuum is released by switch 182.as the sheet is being placedon the platform 46. When the rod is longitudinally withdrawn from itsposition over the platform, the rod is translated through a reverse arewhich is substantially equivalent to the first arc. Finally, the rod islongitudinally advanced to its original position immediately beneath theterminal end 35. Thus the rod 42 will be seen to lift each transverselyfolded sheet from the conveyor 34, fold the same along the longitudinalfold line formed by the rod, and transport the folded sheet away fromthe terminal end 35 and onto the platform 46.

As each sheet is deposited on the platform 46, the platform will belowered a distance equal to one-half the spacing between the teeth onthe racks 222 and 221, which by design will be approximately equal tothe thickness of the folded sheet. Thus each sheet will be deposited atapproximately the same elevation. When the desired number of sheets hasbeen received, the platform will drop to its lowered position such thatthe sheets are substantially resting on the belts 50 which extendthrough the slots 242 in the platform 46. The belts 50 are then actuatedto withdraw the sheets from the platform to a position where they may beremoved for subsequent packaging. The platform 46 then returns to itselevated position and is ready to receive the next sheet. Thus theentire operation of the machine is automatic and continuous, and nomanual attention is required.

In the drawings and specification, there has been set forth a preferredembodiment of the invention, and although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

What is claimed is:

1. An apparatus for sequentially folding and stacking a plurality offlexible sheets comprising frame means,

conveyor means carried by said frame means for conveying individualsheets along a path of travel to a terminal end thereof,

transverse folding means carried by said frame means and positionedintermediate the length of said couveyor means for sequentially foldingeach sheet upon itself along a transverse fold line as the sheet isconveyed by said conveyor means,

longitudinal folding means carried by said frame means and positionedadjacent the terminal end of said conveyor means and including alongitudinally disposed rod for lifting each transversely folded sheetfrom said conveyor means, for folding the same along a longitudinal foldline formed by said rod, and for transporting the folded sheet away fromsaid conveyor means, and

platform means carried by said frame means and positioned adjacent saidlongitudinal folding means for sequentially receiving the folded sheetsfrom said longitudinal folding means to form a vertical stack thereof.

2. The apparatus as defined in claim 1 wherein said platform meansincludes a horizontal platform, and means for vertically translatingsaid platform between an elevated position and a lowered position andincluding means for lowering said platform an increment approximatelyequal to the thickness of a folded sheet upon receipt of each sheet fromsaid longitudinal folding means to thereby form a vertical stack offolded sheets on said platform having a consistent elevationapproximately equal to that of the platform at its elevated position.

3. The apparatus as defined in claim 2 further including means forremoving the stack of folded sheets from said platform upon saidplatform reaching its lowered position.

4. The apparatus as defined in claim 3 wherein said means for removingthe stack of folded sheets includes spaced parallel slots extendingthrough and defined by said platform, a plurality of spaced parallelconveyor belts positioned generally below said platform at an elevationslightly above that of the platform at its lowered position with each ofsaid belts adapted to communicate with one of said platform slots, andmeans for selectively actuating said conveyor belts upon said platformreaching its lowered position to withdraw the stacked sheets therefrom.

5. The apparatus as defined in claim 2 wherein said longitudinal foldingmeans further includes means for sequentially translating said rodthrough a first are extending from a first position below the terminalend of said conveyor means to a second position adjacent said platform,for longitudinally withdrawing said rod from said second position, fortranslating said rod through a reverse are equivalent to said first arc,and for longitudinally advancing said first rod to said first position.

6. The apparatus as defined in claim 5 wherein said rod includes vacuummeans for facilitating accurate folding of the sheet on the rod.

7. The apparatus as defined in claim 1 wherein said conveyor meansincludes a horizontal endless belt defining a discharge end, and saidtransverse folding means includes a transverse bar mounted immediatelybelow said discharge end of said endless belt,

a cooperating pair of nip rollers longitudinally aligned 10 with saidtransverse bar and also forming a part of said conveyor means,

means for rotating said nip rollers in opposite directions, and meansfor selectively longitudinally translating said transverse bar toclosely approach said nip rollers whereby a sheet having ends anddropping vertically downwardly from said discharge end may be engagedintermediate its ends by said transverse bar and drawn between said niprollers to fold the same therebetween. 8. The apparatus as defined inclaim 7 wherein said means for selectively longitudinally translatingsaid tran verse bar includes a photoelectric proximity sensor positionedto sense the presence or absence of ,a sheet on said endless belt androtatable cam means operatively controlled by said sensor for advancingand retracting said transverse bar.

9. An apparatus for sequentially folding and stacking a plurality offlexible sheets comprising frame means, conveyor means carried by saidframe means for conveying individual sheets along a path of travel to aterminal end thereof,

first transverse folding means carried by said frame means andpositioned intermediate the length of said conveyor means forsequentially folding each sheet upon itself along a first transversefold line as the sheet is conveyed by said conveyor means, secondtransverse folding means carried by said frame means and positionedintermediate the length of said conveyor means and subsequent to saidfirst trans verse folding means for sequentially folding each sheet uponitself along a second transverse fold line as the sheet is conveyed bysaid conveyor means,

longitudinal folding means carried by said frame means and positionedadjacent the terminal end of said conveyor means and including alongitudinally disposed rod for lifting each transversely folded sheetfrom said conveyor means, for folding the same upon itself along alongitudinal fold line formed by said rod, and for transporting thefolded sheet transyersely from said conveyor means, and

platform means carried by said frame means and positioned adjacent saidlongitudinal folding means for sequentially receiving the folded sheetsfrom said longitudinal folding means to form a vertical stack thereof.

References Cited UNITED STATES PATENTS 1,673,064 6/1928 Dexter 270-622,054,426 9/1936 Kahn 270-83 2,145,592 1/ 1939 Folger 270-83 2,942,8746/1960 Hajos 270-83 3,190,640 6/1965 Sjostrom 270-66 3,260,518 7/1966Kamberg et a1 270-62 3,361,424 1/1968 Kamberg 270-66 3,363,897 1/ 1968Northern et al. 270-84 3,602,494 8/ 1971 Holmes 270-31 FOREIGN PATENTS1,093,691 12/1967 Great Britain.

RUSSELL R. KINSEY, Primary Examiner US. Cl. X.R. 270-86 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 702, 696 DatedNovember 14, 1972 lnventofls) I Richard K. Teed It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 5, line 12, and it will be seen that the belt is longitudinallysplit" should be A gear 149 is mounted on the near end of shaft 144Column 8, line 9, "20" should be 220 Signed and sealed this 13th day ofMarch 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM PO-1050 (10-69] USCOMM DC 6o375 p69 u.s. GOVERNMENTr-mm'mc OFFICE 1969 O366'H4

